215231743421 has 2 divisors, whose sum is σ = 215231743422. Its totient is φ = 215231743420.

The previous prime is 215231743417. The next prime is 215231743483. The reversal of 215231743421 is 124347132512.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 189756072100 + 25475671321 = 435610^2 + 159611^2 .

It is a cyclic number.

It is not a de Polignac number, because 215231743421 - 2² = 215231743417 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215231743021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107615871710 + 107615871711.

It is an arithmetic number, because the mean of its divisors is an integer number (107615871711).

Almost surely, 2^215231743421 is an apocalyptic number.

It is an amenable number.

215231743421 is a deficient number, since it is larger than the sum of its proper divisors (1).

215231743421 is an equidigital number, since it uses as much as digits as its factorization.

215231743421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 35.

Adding to 215231743421 its reverse (124347132512), we get a palindrome (339578875933).

The spelling of 215231743421 in words is "two hundred fifteen billion, two hundred thirty-one million, seven hundred forty-three thousand, four hundred twenty-one".